The discharge of semi-automatic pistols creates extremely high levels of noise. The report of a pistol can cause serious hearing damage to the user and surrounding persons. The sound created by the discharge of a pistol is the result of the escaping propellent gas the hyper sonic travel of the projectile, and the mechanical action, i.e. the reciprocation of the slide of the semi-automatic pistols. Sound suppressors, often inaccurately referred to as “silencers” generally baffle and dampen the sounds of the escaping propellent gas. The use of sub-sonic ammunition helps lessen the sound of projectile travel. The noise created by the mechanical action of the pistol cannot be mitigated unless the slide is physically prevented from reciprocating upon discharge. Heretofore, semi-automatic pistols generally include slide stop mechanisms that lock the slide to the rear when the magazine is empty, but have no mechanism for physically locking the slide in battery, i.e. the forward closed position, and preventing the slide from reciprocating on discharge.